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Hello and a few questions about knives and sharpening - Page 2

post #31 of 41

You're laboring with some very basic misunderstandings about sharpening.   I'm not saying you can't sharpen a perfectly good edge without being able to conceptualize the geometries and the process, but some degree of understanding is a big help to most people.


Get yourself some graph paper and/or a protractor and draw yourself some huge angles.  Do multiple pictures and set them around your sharpening area so your eyes help but light on one.  You can use those to compare your knife angles -- close enough.   As a bonus, your wife will think you're nuts.


With a "V" edge -- which is the type of edge you're sharpening -- it's almost always to sharpen both sides to the same angle(s).  If for no other reason than it makes steeling and re-sharpening easier.  But it also makes for a stronger edge.  Sharpening to equal angles is true for all but the most asymmetric of edges. 


The sharpness of your edge has very little to do with the angles.  You can sharpen a very, very sharp edge to very obtuse angles.  By way of example, shaving with an axe or a cleaver is a trick a lot of sharpeners use to showcase their skills.  My "chef de chef" (a 12" carbon Sab) is sharpened to a 20* over 25* double bevel and when it's fresh off the stones will cut through chicken wings by accident -- that is, just resting the knife on the bird and answering the phone.  That's not only pretty darn sharp, I daresay it's sharper than any knife you've ever used.  The point being not only are there other aspects besides angles, but that the angles themselves aren't even that important.  My feeling is that you're overemphasizing them.  


You want your edge angles to be as acute as your knife will hold -- but no more acute than that.  Err on the side of obtuseness or you'll be using your steel every time you use your knife.  In other words, too often.  When you're trying to sharpen the "best" edge, there's always some tension between absolute sharpness and durability.  Try not to tip too far over to one side.  Your Globals do fine at 15*, your Germans at 20* and that's just hunky-dory.  Don't try to turn a Henckels into a Tadatsuna.  They aren't built to be the same and you can't make it so on the stones.  For that matter, you can't make a Global act like a Tadatsuna.  Although Globals are made and designed and Japan, as a result of their width and alloy they act as much like German made knives as Japanese.  If you're want a knife that performs like one of the Japanese "lasers," I'm afraid you'll need to buy one. 


As I wrote earlier if you want to optimize the performance you can try a double bevel -- but for most knives that represents a lot of work for a smallish improvement.  But as long as you're not too aggressive about thinning, you're not going to hurt anything by trying.  Also, at the risk of setting the cart before the horse, you can make the double bevel process more efficient by "micro-beveling" the primary (cutting) edge angle.  If you were doing 20/15 for instance, that would mean sharpening the edge to 15* going all the way through your stone set, then using your fine stones only for a few strokes to sharpen and polish the 20*.  It's not quite as durable as a true double bevel, but will stand up quite a bit longer than using an edge that's otherwise too acute.


I have the feeling that you still don't get that you can't sharpen a 15* angle over a 20* angle without completely re-profiling the knife.  If you try you'll only sharpen the top of the bevel without the cutting edge ever touching the stone.  You might need to try the "Magic Maker trick" just to get some idea of how angles work.  If you haven't already tried it, now is a great time to start.


Hope this helps,


post #32 of 41
Thread Starter 

Thank you for the suggestion.  I'll try that with the graph paper to figure out exactly what angles these are.  But with the slight imperfections in my technique, the bevel is not completely flat, and it may not be all that precise.


I DO understand that I need to grind a bevel all the way to the edge to change the angle and reprofile the knife.  I already did it on all of my knives.  I THINK I have a 15/20 now on the Wusthof, but am not exactly sure -- the factory edge has a bevel that still showed individual grit lines, so I smoothed it out, at about the same angle, with the 1000 grit stone.  When I ground the other side down to approximately double the bevel width, I smoothed both sides out on the 2000+.  I am waiting on the Takenoko that I just ordered to go the next step.


Also, if the angles themselves do not tell the whole story, how do I make my knives sharper?  I am moderately skilled (though far from perfect) with freehanding, which I quite enjoy, but now I think I'm in a whole new level of sharpness here -- I just got my Tojiro petty in the mail, and HOLY CRAP IT IS SHARP.  It looked so sharp I tried a trick I saw on a Youtube video once that someone did with a razor -- hold a strand of hair to the edge.  In the Youtube video, the hair fell into two pieces just being pushed against the edge.  The Tojiro didn't quite do that -- the hair stayed in one piece when I just touched it to the edge -- but when I blew on the hair, it fell into two pieces.  It just needed a little bit of encouragement.


Now I really want a proper laser -- 12 inches of what this thing has.  But I also want to know how to put the edge on myself.  I would also buy a Sabatier if I can find a real one that was made in France.

post #33 of 41

You make your knives sharper by sharpening flat, even bevels, "chasing the burr" to a fare-thee-well, thoroughly deburring, and sharpening (and maintaining) a well trued edge.  In addition, you can enhance performance and convenience by polishing to appropriate levels, profiling to appropriate angles and using an appropriate steel as necessary. 


Assuming you're using an appropriate steel, I find it helps to use a steel as part of the deburring process.  Not only does it help get the burr off and create a fine, new metal edge, but it trues as well.  However, you don't want to use the steel once you've started polishing the edge because even the finest rod hone will do some scuffing and -- if over used -- increase the likelihood of chipping.


The Tojiro factory edge, is pretty good (especially as Japanese knives go) but you can do better.  In your case it's most likely a question of holding your angles steady.  It takes a lot of practice before your wrist develops an appropriate muscle memory -- even longer if you're sharpening several different angles.


You're much better off sharpening both sides to the same angle.  Different angles weaken the edge, making it more prone to rolling and chipping.  Also, it's incredibly annoying to have to change angles with every stroke on your rod hone.


Using the same angles doesn't mean the symmetry is going to be equal.  For instance, you can have the edge angles the same, but one bevel twice as wide as the other.  If you did, your symmetry ratio would be 66/34 -- which most knife guys would shorthand as 70/30 or 60/40.  If you're going to use a steel as part of your maintenance regimen, it's better to not go much beyond 60/40.  In other words, twice as wide but err on the side of caution.


Appropriate asymmetry makes a knife act sharper.  Whether or not it actually is sharper is more a question of language than use.  Much like acuity, the more asymmetric the edge the less durable it will be -- for the same reasons different angles weaken the edge.  There are also issues with "steering" which tend to come up if there are two users of different "handedness," if the knife is highly asymmetric, or if the user has a tight or overhand grip.


Consequently, you have to determine what degree of asymmetry is appropriate for you rather than just pushing it to some magic number.  Still, most users seem to find 60/40 represents a pretty good balance.  For the little a personal example is worth, I sharpen the knives my wife (right-handed) and I (southpaw) share to a 60/40 right handed edge. 


The reason asymmetry with equal angles is better than differing angles, is that there's some practical advantage to asymmetry.


A lot of Sabatiers are made in France.  I don't think you get much value from one of the stainless knives, but the carbons are wonderful.  K-Sabatier and Thiers-Issard are two makers whose knives are easy to get in the U.S., and when you're ready to buy we can get specific.


If you're interested in a "laser," you might want to read my review of the Konosuke HD to get some idea of what's involved.  While I think choosing a knife by Rockwell hardness is usually not the smartest thing to do, you don't really want to get into a knife that thin unless it's made from something harder than 60 RCH (because you'll be sharpening to such a high degree of asymmetry in order to enhance the already unbelievable sharpness) you won't be maintaining on a rod.  Consequently, the universe of lasers -- never that large -- further restricted.


Hope this helps,


post #34 of 41
Thread Starter 

I'm sure that the Konosuke would be awesome, but I don't know that I want to mess with the high end stuff just yet.  I think I will practice on the Tojiro I have for a while and get my sharpening technique up to par before I move up the ladder -- no sense spending $300 on a knife that *can* be a laser if I can't sharpen it to that point.


Hopefully the Yen-Dollar rate will have calmed down and the knives will be cheaper by then.


Is there already a thread on waterstone sharpening technique for Japanese knives?

post #35 of 41

It's a topic that's been covered many times.  The current state of advice is to watch the videos on Chef Knives To Go, they're pretty good if not excellent.  Bear in mind that there are a lot of good ways to sharpen knives -- including a lot of good ways to sharpen them on water stones. I keep threatening to write a pamphlet, but haven't got around to it.  I'm a pretty good sharpener and pretty good at communicating sharpening technique, but I'm by no means the only good source nor are my methods particularly powerful.  In other words, becoming good is going to involve a certain amount of picking, choosing, mixing, matching, sorting through conflicting advice (all of which may be very good) and finding your own way... so be tolerant of the learning curve. 


You want to start by prepping your stones properly.  That means lapping them in the same way you would if you were flattening, and chamfering or nosing over all eight edges and corners.


I suggest learning the processes of raising a burr and deburring as the easiest and most efficient way not only to sharpen but to learn to sharpen.  Start with a medium coarse stone -- about 1K grit level (according to the Japanese standard), then when you can consistently raise a burr and chase it, move up to a medium fine -- about 3 - 6K or so.  When you can consistently get the knife sharper on the medium fine, you're ready to add a coarse stone for occasional profiling and repair, and an ultra fine stone (if you want one)  for polishing.  There's no need to jump into buying a lot of stones until you can use the heart of the kit.


Ask lots of questions.



post #36 of 41
Thread Starter 

Maybe it would be better to just tell you what I already know.


I started freehanding at 11 with my boy scout knife, in exact accordance with the Boy Scout Manual(C).  The instructions were to run the blade along the stone at ~30 degrees, blade first, in single strokes (one direction only), being sure to give the same strokes to each side.


I found the edge that this technique gave the boy scout knife inferior to the one that a crappy hand sharpening thingie gave our carbon butcher knife and experimented quite a bit, ultimately settling on single strokes away from the edge at about 22-25 degrees being the most that that thing would hold.  It was a first lesson in how different metals take and hold edges differently (boy scout knives are full of chromium, I later learned).  I also got used to sharpening with a slight convex because I found that I could get the metal to sustain a sharper edge than it otherwise would given its softness.


I tried the same technique with the carbon butcher at a better angle and got it so sharp my mom was a little scared of it.  Unfortunately, every time it cut a lemon or something acidic, or was left in the sink unwashed, or was otherwise abused, the edge would deteriorate.  Another lesson in metal behavior.


Later, when I bought better knives and a real sharpening stone, I used the same technique.  I didn't know what a burr was but was able to develop it each time and feel it with my thumb -- I thought it was a result of some defect in  my technique -- and it led me to use progressively lighter pressure and fewer strokes as I sharpened to try to get rid of it, until I got it small enough to polish off with old newspaper or cardboard.


But my technique remained the singe stroke, back of the knife first method, which I found very effective.  It sharpened quickly enough, allowed me to run the whole length of the blade along the stone in each stroke regardless of the size as long as I angled it, and also allowed me to easily put a smooth convex edge on the blade if I wanted to.  The resulting edge is a better than factory edge for my Henckels chef knife but inferior to the Global factory edge.  And the edge is all scraped up because I only used a cheap twosided rough/very rough stone, that got wet only because I was rinsing off the metal particles that came off the blade as I used it.


It was also part of the reason that I never flattened my stone before (in addition to the fact that the cheap stone is really, really durable).  If you only ever do the back-first stroke, the dish didn't matter much.


And this was the same technique I used for many years, until just a month or so ago, when I saw the Global videos on how to sharpen.  Until that time I was unhappy that I could not get my Global to the factory edge with my technique.  Now, using much more acute angles, the two stroke technique (back and forth), working with the slurry on a 1000 grit King and an Aoto natural I currently put a better edge on my Henckels chef than factory, and comparable on the Global factory edge.  But then I got the Tojiro and realized that there is a whole other level of sharpness, maybe more, that I want to try for.


So...  Here is my question:  why is the two stroke technique preferred with water stones?

post #37 of 41

Your question is based on a false premise.  In law we'd say "Objection.  Assumes facts not in evidence." 


What you're calling the two stroke is working better for you at the moment, but it isn't inherently superior.  Why it's seems to work so much better for you than other styles is an open question.  Some of the advantages are:  It promotes sectioning; allows (relatively) easy pressure control; pulling a wire (aka "draws a burr") quickly, and works up a good slurry fairly quickly. 


I almost always use it on my coarser stones -- whether water or oil -- when first pulling the wire, but move on to length of blade strokes for chasing the wire.  Also, I usually use length of the blade strokes (and a very light touch) for polishing -- when I'm not trying to draw a burr at all.


Most likely your success and limitations as a sharpener are based on some combination of the quality of your burr creation and deburring; and the quality of your bevels. 


You want that burr very fine and flopping from side to side before you deburr.  You want to deburr completely -- leaving a very fine (no chips) edge.


You want the bevel shoulders to be an equal width down the length of the knife from heel to tip (although you can allow them to widen a bit close to the point).  That means your bevel angle is constant and without any high or low spots.  High and low spots are a very bad thing. 

You can test for them -- and see them easily -- using the Magic Marker Test. 


It might help you to conceptualize the ideal cross section of a knife edge as a "V," and the ideal cross section of a knife edge with a burr as a "Y," or better still, a "y."  You want to bend the burr back and forth so that it breaks very cleanly and evenly where the legs of the "V" (should) meet.  The thinner you get the burr and the more often you fold it back and forth across the same crease, the cleaner it will come off.  That makes for a very sharp edge.  You're probably not doing that as well as it can be done.


Uneven bevels -- resulting from imperfect angle holding more often than not -- also rob the edge of its potential.  The more perfect your bevels the sharper and more durable the edge.  These two things -- a fine edge, and even bevels along the length of the knife -- are about the only areas where absolute sharpness and durability go together.


To help you out:  Unless you're very good at seeing the bevel shoulders, use the Magic Marker test.  I know it seems very "beginner," but it's nice to go back once in a while and get a good look at what you're doing.  The "Bic test" is also very revealing, especially in terms of micro-chipping -- which takes us back to how well you deburr.  At some level of experience you tend to abandon most of the "objective" tests in favor of thumb dragging and glint testing -- but getting back to basics is never a bad idea. 


Again -- the Tojiro factory edge might seem like a revelation now, but you can do better. 



post #38 of 41

Sorry for butting in, but

I know idea of using the magic marker, but what's the "bic" test?

Life is too short to drink bad wine


Life is too short to drink bad wine

post #39 of 41
Thread Starter 

I think you misunderstood my question, BDL.  Let me state it more clearly:  I understand that there are probably pros and cons to each technique, and am trying to figure out the pluses of the two stroke method.  I have found some good points and problems with it already, but am looking to learn more -- there must be significant reasons why it is almost universally preferred by Japanese craftsmen.


Also, if you will lookat my question more closely, you'll see that what I asked was not why it is is "superior" but why it is "preferred."


I suspect that the slurry is a part of the answer.  I still end the sessions on each individual stone with a few single-direction backwards strokes, but these just wipe the slurry off the stone almost completely, like a squeegee.  If I only did that throughout, I would hardly have any slurry on the stone through the session.


As for which is superior on the whole, it's hard to tell because I switched to the double stroke method at the same time that I got the finer stone and also started to attempt more acute angles.  I should have isolated the variables to observe the differences each made.  I just thought that that was the "correct" way to use waterstones.  I do find that it works faster and keeps the slurry on the stone, but I also find that every now and again I would end up with a little mismatch between sections which I never used to get with the one stroke, diagonal method.  This happens more often at the tip where the blade curves.


Some other disadvantages I have found are that it concentrates the wear more on the stone -- with the single stroke, more of the stone is used, and the stone gets worn more evenly.  WIth the double stroke, the center of the stone gets used a lot, more heavily on the side facing away from you.  This requires that one rotate the stone periodically.  The last half inch to an inch is hardly ever used at all and just gets taken off in flattening.  It also seems to make the stone more prone to gouging by the tip, which was never a problem for me before.


But I figure that the people more experienced with them must know more pros and cons -- and how to take advantage of or avoid them -- than these.  So, that is the full question: what are the advantages of the two stoke method over the one stroke?  And what are the disadvantages?  And what can I do to maximize my performance with the two stroke method?  My main problems at this time are that I 1) am not always able to maintain an absolutely consistent angle for a razor-type, completely straight bevel with no convex at all, and  2) also sometimes end up with spots with more or less wear on the blade -- if you look at the photos I posted, there are places, especially where the sections sharpened overlap, that seem to wear more than the rest.  I am experimenting with avoiding this by using a progressive movement (lines representing the movement of the knife):




...and moving the knife steadily from heel to tip, instead of the straight back and forth and then move the knife movement:


||||  (move the knife)  |||| (move the knife) ||||


...but so far it has proven ineffective because it makes it even harder to maintain a consistent, convex-free angle.


I am beginning to think that I might want to build a wooden rack, like the Japanese sword polishers use -- the one that is raised on an inclined surface so that the level at which the blade meets the stone is visible at all times -- so I can eyeball the angle against the stone at all times, instead of relying only on muscle memory.

post #40 of 41

Cap, are you a lefty? It looks to me as though the left bevel is now quite a bit wider than the right, which is how you sharpen a knife asymmetrically for a lefty. I'm just checking.


As to the "two-stroke" method, as you call it, yes, it's about mud. The mud is what makes Japanese-style waterstones work so wonderfully, and you need to go back and forth to keep from just pushing (or pulling) all the mud off as you go. As you say, one big disadvantage is that you work the stone unevenly and make it dish, which is partly the method and partly the fact that the mud is coming from the stone, wearing it away. If you want to invest a lot of money, there are various natural stones that wear very, very slowly, but they cost a mint.


I would advise against the angle-switching technique you're proposing. I think you'll end up with inconsistent sharpening angles. You will certainly end up with irregular scratching, but that's pretty minor all things considered.


Note that you can gain some advantages, insofar as wear and evenness and such are concerned, by using a Japanese-style sharpening box, which looks sort of like a shoe-shine box backwards. You put it over a sink, and the stone is angled away from you, with the far side lower than the near. I forget the angle -- I could look it up if you want, but I think it's about 10 degrees or so. When you sharpen this way, the push-stroke doesn't dig in so much, and the pull-stroke digs in more, and that sort of evens things out. I have never used one of these things, but it would be easy enough to build if you want to give it a whirl.

post #41 of 41
Thread Starter 

I am right handed...  I think I might have sharpened it wrong for asym. profiling...  Since I use it for the heavier work, I haven't noticed much of a difference in drift though.


I will lean on the other side in future sharpenings and it will eventually come back to an even split.  Or maybe I'll just redo the whole thing next time I sharpen.  Trooper has his at 15/15 and he uses his for work, so mine should be fine at that angle.  So far it's held up at 15/20 (by my best estimate -- I tried to follow the factory edge on one side and I read that the Germans come at 20...  SO if I followed it right, that's what it is).


The sharpening box sounds like what I ws talking about, but the angle is different.  From what I can remember, the combination of the incline and height is enough so that sharpener can look at where the blade meets the stone -- the space between the spine of the knife and the stone -- very easily, so that the angle can be controlled and monitored both through sight and touch -- one of the frustrating things about sharpening on the flat waterstone is that I lose the visual cues I used to have when I held the stone in one hand and ran the knife up with the other. 


For now I think I will experiment with just using a board placed in my sink on an incline.  Hard to do with the heaviest stones though.

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